Process and apparatus for etching plates.



No. 865,884. PATENTED SEPT.10, 1907.

P. J. M. GBRLAND. PROCESS AND APPARATUS FOR ETCHING PLATES.

APPLIUATION FILED JAN. 4, 1907.

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FREDE KICK .T. M. GERLAND, OF SEA CLIFF, NEW YORK, ASSIGNOR TO CHARLOTTEA. fi-ERLA'ND, OF SEA CLIFF, NEW YORK.

his. senses.

Specification of Letters Patent.

Patented Sept. 10, 1907.

Application filed January 4,1907. Serial No. 350,848-

To all whom it may concern:

Be it known that I, FREDERICK .T. M. GERLAND, a

citizen of the United States, residing at SeaGliff,

county 01' Nassau, State of New York, have invented certain new anduseful Improvements in Processes and Apparatus for Etching Plates, ofwhich the following is a specification. I

The present invention relates to novel process and apparatus for etchingthe surfaces oi plates and particularly those employed in producingphoto-engraved half-tone and other lined plates.

Heretolore etched plates have been produced by immersing the plate in aslowly rocking acid hath whereby the acid was caused to flow back andforth over the surface of the plate, and during this rocking motion theattendant brushed the surface of the plate at intervals by means of ahand applied brush. practicing this old method it was neces progress ofetching to from time to'time strengthen the it was necessary that theattendant should npply the brush by hand to the surface of the platewhile the plate was being tipped first in one direction and then in theopposite direction and in doing,so and in watching the progress of theetching necessarily projected his face over the acid bath and thusinhaled the-injurious acid fumes The periods when the plate should bebrushed for the removal oi the accumulated oxid was leit entirely to thejudgment and careful watching oi the attendant and wholly to his skillin attempting to evenly manipulate the brush uniformly and with gentlepressure equally over the entire surface oi the plate while is wasconstantly changing its inclination.

The method was slow, profligate of the acid and owing to the entiredependency upon the skill and judgment of the attendant it oftenhappened that muddy plates were produced-by reason of the nonuniformbrushing, and furthermore there was constant danger of undercutting fromthe harsh application of 'the brush repeated over the same portions ofthe plate.

The objects of the present improvements are to wholly overcome thedisadvantages incident to the old method and to render the etchingprocess more cortaiu and regular; to eliminate entirely, the personalequation 0! the attendant, in judgment, attention and skill; to producea cleaner, deeper and more evenly etched surface, in much faster timeand with less expenditure of acid.

In practicing the improved process the plate to be etched is placed faceuppermost on the grooved bottom of a horizontal, stationary wooden tankor open box, sulllcient properly diluted etchingacid being supplied tothe tank to cover the plate to the desired depth. 'iho acid is thenregularly moved buck and forth over the plate and forcibly agitated bythe action inry during the of asuitable soft bristle brush which sweepsthe acid forcibly in front of itover the plate whose upper surface it isat/the same time gently and evenly touching and brushing. Y

The brush is both mechanically supported andmechemically moved so thatthe ends of its bristles touch and move over the entire surface withdelicate and exactly even pressure; that is to say, the plane ofmovement of the brush is exactly parallel with the plane of the surfaceof the plate and the brushis adjusted to touch all parts of the surfacewhile in motion with precisely the same pressure, and its move- 'ment,preferably a -reciprocatory movement through the liquid and against andalong the whole surface of the plate is regular and uniform. The brushshould i be slightly longer then the width of the pletes surface so thatno portion thereof in covering the entire surface need be brushed morethan other portions.

The agitation of the acid in the improved process is entirely dissimilarto the gentle back and forth flow oi the acid in the rocking bathof theold method, in

' that the forcible agitation caused by the brush moving with uniformmotion through the liquid brings about a deep and violently disturbed orchurned up wave extending in front of and in immediate contact with thebrush entirely across and progressing equally along and over the entiresurface of the plate, with the result that the acid is thoroughlystirred and aerated and theoxid is brushed oll' asquickly as it forms onthe plate or is not permitted to accumulate because of the constant anduniform application of the brush and the violent agitation of the acidand with theadditional result that the oxid is dissipated and the bathrendered entirely free of the oxid and its serviceableness or life ismaterially increased. The regular mechanical application of the brush inthe present process is also wholly dissimilar to the, hand applicationin the old method, in that no part of the surface of the plate receivesthe brush either less or more times than any other part of the surfaceand furthermore all parts are touched exactly alike and with the sameuniform pressure.

By reason of; the improvement the attendant is not subjected to theinjurious fumes rising from the etching bath neither are the fumes,apparently, so noticeable; so too it is possi is to time the etching ofeach plate and know with certainty upon the lapse of a stated time thatthe plate is suitably etched.

A convenient and simple form of apparatus with which to practice theimproved process is illustrated in the accompanying drawing; the figures1 and 2 in dicuting by longitudinal and cross sectional elevations a.practical application of the process.

In the views, the stationary horizontal tankor box I g p $65,884 Ietched. The brush D is adjustably secured to the end of a vertical rod Ethe upper end of which is rigidly attached to a reciprocating barmounted to move in a right line and parallel with the surface of theplate on grooved guiding and supporting wheels or rollers G. Back andforth horizontal movementmay be imparted to the bar and through it tothe brush in the acid bath by any convenient power communicated througha suitable connecting rod H pivoted to one end of\the bar. The brush maybe adjusted up or down on the rod E to vary its pressure upon the plateand to compen'ite for its wear.

I Other forms of apparatus and manner of mounting and moving the brushmay of course be used without departing from the invention.

What is claimed is: I

t 1. The hereindescrihed etching process, which consists in immersingthe plate in a bath oietching acid and agitating the acid by the act ofthe uniform movement of a hrush in brushing the plate.

L. The hereindescrihed etching process, which consistsv in immersing tneplate in a bath of etching acid and subjeeting the plate to the constantaction of. a brush uniformly applied and thereby agitating the acid.

An etching apparatus comprising" a tank for the acid. a brush extendingtherein, a right line support for the brush and means for reciprocatingit back and forth through the acid in the tank.

4. An etching apparatus comprising a tank for the acid, a verticallyadjustable brush extending therein, a right line support for thehrushand means for moving the brush forward and backward through the acid inthe tank.

In testimony whereof. i have signed my name to this specification in thepresence oi two subscribing witnesses. this 12 day of December 1006.

FREDERICK J. M. GERLANI).

Witnesses C. \Innnnoz, EDWARD EAnL.

